This invention relates to laminated windows and more particularly to such windows which include a solar reflecting coating.
Laminated windows containing glass and plasticized polyvinyl butryal (PVB) as a shock absorbing component for safety purposes are well known for architectural applications, vehicle windshields and the like. Layered transparent coatings containing one or more Angstrom-thick metal layers for reflecting heat-producing infra-red (IR) solar radiation are likewise known for use in such windows. The metal layer(s) may be electrically conducting to reduce defrost time particularly when the window is in a vehicle such as an automobile. As recognized in U.S. Pat. No. 5,131,967, windows containing such coatings have been known to experience corrosion after prolonged exposure along the edges to the atmospheric environment. Such corrosion usually starts at the peripheral edge of the coating which is not sealed from the environment. Over time, such corrosion may progressively extend inward from the edge and ultimately adversely affect coating appearance and performance.
A technique in the prior art minimizing such corrosion involves alloying a silver metal layer of the coating with gold (U.S. Pat. No. 4,234,654) or palladium (U.S. Pat. No. 4,565,719). These are quite expensive solutions.